Skylight installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What skylight installation is

Skylight installation cuts an opening in the roof, frames and flashes it, sets the skylight, and finishes the interior shaft. The waterproofing at the flashing is what keeps the skylight from leaking. People call to bring daylight into a room, to replace an old or leaking skylight, or to vent a hot upstairs space.

Signs you need it

  • A dark room with no natural light, where a roof opening would bring in daylight
  • Water stains on the ceiling or wall beneath an existing skylight after rain
  • Fogged, cracked or yellowed glazing, or a dome that has clouded over
  • A skylight frame that has rusted, warped or pulled away from the roof flashing
  • A hot upper room that needs ventilation, where a vented skylight may suit

What the pro does

  • Check the rafters, the ceiling and any wiring or ducts in the planned opening before any cut is made
  • Cut the roof opening, frame it with headers and trimmers sized to the skylight, and set the curb or frame square
  • Install the flashing kit in the right order, with underlayment and step flashing that shed water over the lower edges
  • Set the skylight unit, then fasten and seal it to the manufacturer's specification
  • Finish the interior shaft with insulation, drywall, trim and a diffuser or shade, then run a water test on the flashing

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Number of skylights, and their size and type, such as fixed, vented, tubular or curb-mounted
  • Roof pitch and roofing material, which set the flashing method and the access needed
  • Framing changes such as cutting rafters and adding headers
  • Interior shaft length and the finish work, including drywall, paint and trim
  • Electrical work for powered or motorized skylights and their controls
  • Height and access, including the staging and fall protection the roof needs
  • Permit and inspection requirements for roof openings and structural framing

What a written quote should spell out

  • Skylight brand, model, size and glazing type, with the flashing kit named
  • Framing work, including headers and trimmers, shown as its own line
  • Underlayment and step flashing details, with the method for each roof edge
  • Interior shaft length, insulation and finish, including drywall, paint and trim
  • Manual or powered operation, and the controls included with each
  • Leak test method and the warranty terms on the skylight and the install

Questions to ask before you hire

  • What flashing kit do you use for my roofing material, and how is the flashing layered?
  • Will you check the rafters and the wiring in the opening before cutting?
  • How do you insulate and finish the interior shaft so it does not sweat in winter?
  • Will the opening need a structural header, and who checks the sizing?
  • Do you test the skylight for leaks before you leave, and how do you run the test?
  • What warranty covers the glazing and the flashing, and what does it leave out?
  • Who is on the roof, and what fall protection does the crew use on my pitch?

Red flags

  • A skylight set with no flashing kit, only sealant at the roof edge
  • A roof opening cut before the rafters and the wiring in the opening were checked
  • A skylight fitted without a curb or proper frame on a roof that needs one to shed water
  • An interior shaft left uninsulated, so condensation drips onto the ceiling below
  • No leak test planned before the roofing is closed up

What you can do yourself

You can safely look at the ceiling below the skylight from inside for water stains, and check the glazing, dome and frame from the ground with binoculars. Cutting a roof opening, handling heavy glass and working at the roof edge are work at height and structural changes, so leave them to a pro. Call a pro for any leak, cracked glazing, or a skylight that needs to be replaced or added.

Licenses and permits

Skylight installation is commonly done by licensed roofing or general contractors, and roof openings and framing changes often need a permit and inspection. Check with your state and local licensing and building offices before work starts.

Skylight installation questions

Can a skylight go into any roof?

Most sloped roofs can take a skylight, but the framing, the roof pitch and the roofing material decide the flashing method and the work needed. A pro should check the rafters and the layout first.

Do skylights leak more than windows?

They can, if the flashing or the curb is wrong. A correctly flashed skylight should be as dry as any other roof penetration. Ask the installer how the flashing is layered and tested.

Will a skylight make my room too hot?

It can. Glazing type, a shade and ventilation all affect heat gain. Ask the installer which glazing suits your sun exposure and whether a vented model fits the room.

How do I keep the skylight from sweating in winter?

Insulate the shaft and keep the air path clear. Condensation on the glass or the shaft often comes from cold surfaces meeting moist room air.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

Edit history

How it works

  1. 1. Describe the job

    Pick the service, add your ZIP and a sentence about what is going on.

  2. 2. Pick the pros you want

    See screened pros who serve your ZIP and choose who you want to hear from.

  3. 3. They reach out

    They contact you the way you chose: phone, email or in-app messages.

More windows and doors guides

Find a pro near you

Find a pro

About this guide

Request skylight installation